Richer, J.M. (2020). A must-read for Human Ethologists. Human Ethology, 35, Human Ethology 35 (2020): 27-31 27-31. https://doi.org/10.22330/he/35/027-031 Book Review A MUST-READ FOR HUMAN ETHOLOGISTS John M. Richer Department of Physiology, Anatomy and Genetics, University of Oxford, UK. Paediatric Psychology, Oxford University Hospitals NHS Trust, UK. [email protected] A Review of the Book Darwin's Unfinished Symphony. How Culture made the human mind By Kevin Laland . 2017. Princeton University Press. 464 pages. ISBN 9780691151182 (Hardback, $35.00, USD) __________________________________________________________________ All Human Ethologists should read this book. It is not that it is just well written but that the quality, style and creativity of thought behind it is an object lesson in how this area of science ought to be conducted. Darwin's unfinished symphony (of course a nod towards Franz Schubert), refers to his strong intimations that culture evolved just as did physical and behavioural characteristrics of animals. Laland, a thoroughgoing Zoologist, points out how human culture is so hugely different from anything in even primates or other large brained mammals and how this has had consequences for the success of our species, in particular in the way cultural knowledge cumulatively rachets up, it autocatalyses, such that "in the last 10-12 thousand years of cultural evolution, humanity has been to the moon, split the atom, built cities, complied encylopaedic knowledge, and composed symphonies."(page 235). By approaching the topic from a thoroughly zoological perspective and noting the uniqueness and strangeness of this complex, cumulative autocatalytic culture, he is able better to see the many factors, and what combination of factors, might be crucial to the evolution of human culture. So the central question he asks is how did this remarkable submitted: 14.April. 2020; accepted: 14.April. 2020 Richer, J.M. (2020): A must-read for Human Ethologists Human Ethology, 35, 27-31 autocatalytic complexity of culture evolve? This he addresses by painstakingly, systematically and critically drawing together a multitude of facts and ideas. It is difficult to do justice to the subtlety and complexity of his arguments in a short review (read the book). Fortunately at the end of the book, in an epilogue, he summarises the story he is telling, and rather than précis the book, it is far better simply to reproduce his summary (pages 316-320). My only addition is to embolden some of the key concepts. We have learned through extensive experimental work by behavioral scientists that both copying and innovation are widespread among animals, but that animals can be highly strategic about the manner in which they exploit learned information. The social learning strategies tournament explained much about this learning by demonstrating a selective advantage to copying when implemented with accuracy and efficiency. Strategic, high- fidelity copying confers fitness benefits. This theoretical insight leads to the expectation that natural selection would have favored more efficient and higher-fidelity forms of social learning, a: well as those neural structures and functional capabilities in the primate brain capable of bringing this about. In the process, natural selection will have shaped the evolution of the primate brain and intelligence. Comparative data across primates support this suggestion and reveal strong associations between social learning, innovativeness, and brain size in primates; social learning also covaries with a number of measures of intelligence, including naturalistic measures like tool use and performance in laboratory tests of learning and cognition. The findings imply that a “cultural drive1” process may have been operational across several distinct primate lineages, whereby natural selection favored efficient copying. Selection for high intelligence in primates almost certainly derives from multiple sources; however, comparative analyses suggest that widespread selection for social intelligence in monkeys and apes was followed by more restricted selection for cultural intelligence in the great apes, capuchins, and macaques, mediated by conferred increases in longevity and diet quality. This selection is thought to have enhanced several aspects of cognition, including learning, perspective taking, computation, tool use, and in particular, collaborative social interaction. The comparative analyses, in turn, raise the question of why humans alone should exhibit a culture that ratchets up in complexity. The answer, derived from theoretical work, is that complex culture requires high-fidelity information transmission. Analyses show that small increases in the accuracy of social transmission can lead to big increases in the amount and longevity of culture, and that high-fidelity knowledge transfer is necessary for cumulative culture. In addition, the tournament taught us that high levels of reliance on social learning automatically generated extreme longevity of cultural knowledge. Populations appeared to pass a threshold level of reliance on social learning, above which cultural knowledge became extremely stable and persisted almost indefinitely. With increasing social, as opposed to asocial, learning, our ancestors’ behavior also became more conformist, and started to exhibit fads and fashions as we commonly see in human populations today. Put together, these theoretical results suggested that once our ancestors had evolved sufficiently strategic and accurate forms of copying, many aspects of the cultural capability witnessed in modern humans would arise. 1 This is concept from Allan Wilson, where cultural changes influence, or "drive", genetic evolution. (Wilson 28 A.C. (1985) The molecular basis of evolution. Scientific American 253, 148-157) Richer, J.M. (2020): A must-read for Human Ethologists Human Ethology, 35, 27-31 How did our ancestors achieve high-fidelity information transmission? The obvious answer is through teaching, which is rare in nature but universal in human societies, once the many subtle forms it takes are recognized. Mathematical analyses reveal tough conditions that must be met for teaching to evolve, but show that cumulative culture relaxes these conditions. This implies that teaching and cumulative culture coevolved in our ancestors, creating for the first time in the history of life on earth a species that taught their relatives across a broad range of contexts. Humans are unique in the extensiveness of their teaching mainly because cumulative culture makes knowledge that is otherwise difficult to acquire available in the population to be taught. Teaching is expected to evolve when (1) its costs are low or can be offset against the costs of provisioning; (2) instruction is highly accurate and effective in transmission; and (3) there is a strong degree of relatedness between tutor and pupil. Any adaptation that reduces the costs of teaching ought to be favored by selection provided that it does not seriously diminish teaching efficacy. It was here, in the unprecedented context of the widespread teaching exhibited by our hominin ancestors, that language first evolved as an adjunct to teaching. Language is an adaptation, fashioned by natural selection to reduce the costs, increase the accuracy, and expand the domains of teaching. This explanation has the advantage that it accounts for the honesty, cooperativeness, and uniqueness of language, as well as its power of generalization, how it was grounded, and why it was learned. Human language is unique, at least among extant species, because only humans constructed a sufficiently diverse, generative, and changeable cultural world that demanded talking about. Once our ancestors evolved a socially transmitted system of symbolic communication, other features of language, such as compositionality, came along for free. Experimental studies support the hypothesis that a gene-culture coevolutionary dynamic arose between socially transmitted skills, including tool use, and aspects of human anatomy and cognition. This interaction was ongoing in human evolution from at least 2.5 million years ago, and has continued to the present. Theoretical, anthropological, and genetic studies all attest to the importance of gene-culture coevolutionary feedback in recent human evolution, which has shaped both our anatomy and our cognition, and speeded up rates of change. As expected, the brain regions associated with imitation, innovation, and tool use are among those that expanded during recent hominin evolution. Just as biological evolution gave way to gene-culture coevolution, cultural evolution then took over the reins of human adaptation, and the pace of change experienced by the members of our evolutionary lineage accelerated further. Culture provided our ancestors with food- procurement and survival tricks, and as each new invention arose, the population was able to exploit its environment more efficiently. This not only fueled brain expansion but population growth as well. Human numbers and societal complexity both increased dramatically with the domestication of plants and animals and the advent of agriculture. These freed societies from the constraints imposed on hunter-gatherers by the requirement to be constantly on the move. Agricultural societies flourished both because they outgrew hunter- gatherer communities, through generating an increase in their environments’ carrying capacity, and because agriculture triggered a raft of follow-on innovations